quadrats {spatstat} | R Documentation |
Divides window into rectangular quadrats and returns the quadrats as a tessellation.
quadrats(X, nx = 5, ny = nx, xbreaks = NULL, ybreaks = NULL)
X |
A window (object of class "owin" )
or anything that can be coerced to a window using
as.owin , such as a point pattern.
|
nx,ny |
Numbers of quadrats in the x and y directions.
Incompatible with xbreaks and ybreaks .
|
xbreaks |
Numeric vector giving the x coordinates of the
boundaries of the quadrats. Incompatible with nx .
|
ybreaks |
Numeric vector giving the y coordinates of the
boundaries of the quadrats. Incompatible with ny .
|
If the window X
is a rectangle, it is divided into
an nx * ny
grid of rectangular tiles or `quadrats'.
If X
is not a rectangle, then the bounding rectangle of
X
is first divided into an nx * ny
grid of rectangular
tiles, and these tiles are then intersected with the window X
.
The resulting tiles are returned as a tessellation (object of class
"tess"
) which can be plotted and used in other analyses.
If xbreaks
is given, it should be a numeric vector
giving the x coordinates of the quadrat boundaries.
If it is not given, it defaults to a
sequence of nx+1
values equally spaced
over the range of x coordinates in the window X$window
.
Similarly if ybreaks
is given, it should be a numeric
vector giving the y coordinates of the quadrat boundaries.
It defaults to a vector of ny+1
values
equally spaced over the range of y coordinates in the window.
The lengths of xbreaks
and ybreaks
may be different.
A tessellation (object of class "tess"
) as described under
tess
.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
tess
,
quadratcount
,
quadrat.test
,
quadratresample
W <- square(10) Z <- quadrats(W, 4, 5) plot(Z) data(letterR) plot(quadrats(letterR, 5, 7))